Tag: bio-chemistry

Quizzes (82) Questions (1918)

Questions Related to bio-chemistry

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

ATP synthesis proposed by Peter Mitchell is 

  1. Phosphorylation

  2. Photophosphorylation

  3. Oxidative phosphorylation

  4. Chemiosmotic synthesis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Peter Mitchell proposed a theory to explain the production of ATP which is 'Mitchell's chemiosmotic coupling hypothesis'. According to this theory:

  1. Inner membrane of mitochondria acts as a transducer of energy and converts energy to chemical energy of ATP along the electrochemical gradient.
  2. Inner mitochondrial membrane is impermeable to NADH, ATP, H+, OH-.
  3. ATP synthesis and electron transport are coupled with proton gradient.
So the answer is 'Chemiosmotic synthesis'.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

ATP is injected in cyanide poisoning because it is

  1. Necessary for cellular functions
  2. Necessary for $Na^+$ - $K^+$ pump
  3. $Na^+$ - $K^+$ pump operates at the cell membranes

  4. ATP breaks down cyanide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cyanide inhibits cytochrome c oxidase, blocking the electron transport chain and halting ATP production. Injecting ATP provides the necessary energy for vital cellular functions that would otherwise fail.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

Chemiosmotic hypothesis given by Peter Mitchell proposes the mechanism of

  1. Synthesis of ATP.
  2. Synthesis of FADH$ _2$.

  3. Synthesis of NADH.

  4. Synthesis of NADPH.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Peter Mitchell proposed a hypothesis known as the chemiosmotic hypothesis that an electrochemical concentration gradient of protons across a membrane could be utilized to make ATP. He linked this process to osmosis, the diffusion of water across a membrane, this is the reason it is called chemiosmosis.

So the correct option is 'Synthesis of ATP'.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

Light reaction in stroma lamellae of chloroplast results in the production of

  1. ATP
  2. NADPH$ _2$
  3. ATP + NADPH$ _2$
  4. O$ _2$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A) Along with ATP, ${ NADPH } _{ 2 }$ is also produced.
B) Along with ${ NADPH } _{ 2 }$, ATP is also produced.

C) The light reaction that takes place in the stroma lamellae is the non-cyclic phosphorylation and ATP and ${ NADPH } _{ 2 }$ are the products.
D) Oxygen is also liberated during the light reaction but is not the main product.
So the correct answer is 'ATP + ${ NADPH } _{ 2 }$'.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

ATP does not provide phosphate in the reaction

  1. Glucose Glucose 6-P

  2. Fructose Fructose 6-P

  3. PGAL 1 : 3-diPGA

  4. PEPA Pyruvic acid
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In the conversion of PGAL to 1,3-bisphosphoglycerate, the phosphate group is added via inorganic phosphate (Pi) and oxidation, not by transferring a phosphate from ATP.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

ATP synthetase of chloroplasts is similar to that of

  1. Mitochondria

  2. Peroxisomes

  3. Golgi bodies

  4. Microsomes.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mitochondria and chloroplast both have:

  • A double membrane surrounding the organelles.
  • Purportedly prokaryotic origins according to the endosymbiotic theory which suggests that mitochondria and chloroplast were once prokaryotic bacteria engulfed by endocytosis in early eukaryotes.
  • Their own circular DNA which codes for certain enzymes required for the chemical reactions that take place in these organelles.
  • Their own 70S ribosomes made up of 50S and 30S subunits to translate proteins
  • The enzyme ATP synthase which utilizes the energy released from the movement of protons across it (proton-motive force) to phosphorylate ADP to ATP. (Thus, another similarity would be that they both produce ATP)
  • Electron transport chains, which are embedded in the inner mitochondrial membrane and thylakoid membrane in mitochondria and chloroplasts respectively.
So, the correct option is 'Mitochondria'.

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

ATP formation in chloroplast and mitochondrion is explained by

  1. Cholodny-Went model

  2. Chemi-osmotic theory of Mitchell

  3. Munch's mass flow theory

  4. Relay pump theory of Godlewski
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation
A theory postulated by the biochemist Peter Mitchell in 1961 to describe ATP synthesis by way of a proton electrochemical coupling.
it is based on the proton gradient and transfer of an electron from the mitochondrial matrix in respiration or in the stroma with the photophosphorylation of photosystems forms ATP.
So the correct option is 'Chemi-osmotic theory of Mitchell'.
Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

Chemiosmosis was first described by

  1. Boyer

  2. Walker

  3. Mitchell

  4. Meischer
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The chemiosmotic hypothesis of ATP synthesis in chloroplasts is based on proton gradient. The chemiosmotic hypothesis was explained by P. Mitchell in 1961. He recieved noble prize for it in 1978. ATP synthesis is linked to the development of a proton gradient across the membrane of the thylakoid of chloroplast and proton accumulation is towards the inside of the membrane i.e. in the lumen. 

Multiple choice bio-chemistry biological oxidation chemiosmotic hypothesis living organisms and energy production mechanism of photosynthesis

When cell converts light energy into chemical energy, which of the following reaction would take place?

  1. ADP + iP = ATP

  2. ATP - iP = ADP

  3. AMP + iP = ADP

  4. GDP + iP = GTP
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Cells convert light energy is converted into chemical energy. During this process, a phosphate is added to adenosine diphosphate molecule to cause the formation of ATP.

So the correct option is 'ADP + iP = ATP'.